Detector systems, such as gamma ray detectors, may be sensitive to non-physical events that cannot be discriminated on the basis of the signals from a single pixel. These events cause noise in the system.
The signal generated by an individual gamma ray is very small—of the order of a few hundred to a few thousand electrons. Therefore, relatively small extraneous signals may be detected as gamma rays and erroneously registered.
Vibration in solid-state gamma cameras is one example of a phenomenon that may cause the generation of electromagnetic noise signals that are detected as one or a plurality of events of interest. Analogously, electrical discharges, including discharges driven by potential differences below 5 volts, may generate non-physical events. Impingement of extraneous high-energy particles such as cosmic rays may also cause errors. As a result of Compton scattering into multiple detection elements, a high-energy gamma ray striking the radiation-sensitive surface of a SPERIS can directly produce signals in multiple channels. The gamma ray can also produce noise signals in neighboring channels through coupling by electrical parasitics.